Investigating the thyroid nodule
BMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b733 (Published 13 March 2009) Cite this as: BMJ 2009;338:b733
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The discussion of the value of thyroid ultrasounds has wider
importance. The broader question highlighted in the responses to this
article is not only “What to do”, but also "When is enough enough?". In
our current system once an aspect of an individual is measured and
categorized as ‘abnormal’, even when it is not, it becomes very difficult
to ignore.
There are an increasing number of examples where the availability of
testing and suggestion of risk of disease simply increase the diagnosis of
the condition, rather then offering any prospect of relief of dys-ease.
The consequent cascade of further testing and treatment with the attendant
risks of side effects, increased anxiety and medicalisation of a
previously well individual, is thus triggered. With the increase in PSA
testing the diagnosis of prostate cancer rose, with no indication yet of
improvement in mortality or morbidity. Similarly, with the advent of
ultrasound scanning the diagnosis of thyroid cancer more than doubled in
the USA from 1973 to 2002 with no change in mortality. (1)
The problem is clear and is one that needs to be thought through. It
includes screening for risk factors and “predisease”, which seems to have
few limits. Once an abnormal ‘number’ is measured, or imaging finding
detected, we find it almost impossible not to investigate it further. If
such incidental findings were not investigated what would the harm benefit
ratio be? It is likely that more suffering is caused by unwarranted
investigation than rare cases of serious disease detected. PSA testing,
thyroid ultrasounds, lipid tests and bone density scans should not be
performed in populations where the individuals do not stand to benefit
from treatment in real terms – terms other than correcting their
‘numbers’, or reassuring the physician that everything possible has been
done. Diagnosis itself is not a benefit in the absence of symptoms.
1. Davies L, Welch HG. Increasing Incidence of Thyroid Cancer in the
United States, 1973-2002. JAMA. 2006 May 10, 2006;295(18):2164-7.
Competing interests:
None declared
Competing interests: No competing interests
We read with interest the clinical review by Mehanna et al. [1]. We
thought it gave a very good comprehensive review on thyroid nodule
investigation and management. However, there was one area of the article
that we felt was at odds with our clinical experience.
It is our experience that the incidence of thyroid carcinoma in the
context of a multinodular goitre to be far less than the figures quoted in
the clinical review. The incidence of multinodular goitre in the general
population far exceeds those presenting to an endocrine physician or
surgeon and, of this subsection, only a small percentage go on to undergo
surgical resection. Reasons for surgical intervention include obstructive
symptoms, rapid growth or abnormal ultrasound or aspiration cytology
results.
Literature evidence also indicates a lower incidence of (generally
incidental) carcinoma in resected specimens for multinodular goitre.
Papini et al. looked at a large population (494 patients) with non-
palpable nodules and found the risk of malignancy to be 6.3% in
multinodular goitres [2]. Other authors, in recent studies, have found a
similar rate of between 7.5-9.2% [3,4].
Given this evidence we recommend appropriate investigation and only
surgical resection if the above criteria are met. We feel that the
treatment pathway suggested by the authors would lead to over treatment of
this group of patients.
Competing interests: None
James Coulston Surgical Registrar
Mary Brett Consultant Histopathologist
Justin Morgan Consultant Endocrine Surgeon
References:
1. Mehanna, H., Jain, A., Morton, R., Watkinson, J., Shaha, A.
Investigating the thyroid nodule. BMJ 2009;338:b773
2. Papini, E., Guglielme, R., Bianchini, A., Crescenzi, A., Taccogna, S.,
Nardi, F. et al. Risk of malignancy in non-palpable thyroid nodules:
Predictive values of ultrasound and colour Doppler features. J Clin
Endocrinol Metab 2002;87:1941-6
3. Koh, K., Chang, K. Carcinoma in multinodular goitre. BJS
2005;79(3):266-7
4. Giles, Y., Boztepe, H., Terzioqlut, T., Tezelmans, S. The advantages of
total thyroidectomy to avoid reoperation for incidental thyroid cancer in
multinodular goitre. Archives Surg 2004;139(2):179-82
Competing interests:
None declared
Competing interests: No competing interests
I agree with the previous correspondent that we should not embark on
such a potentially costly extension to current practice without some
assurance that a) it would be cost-effective and b) that patients are
coming to harm as a result of current practice.
I am also concerned that the authors say that a TSH estimation should
be performed but that you shouldn't delay referral or FNA while you wait
for the result. So why do it?
If a patient has a solitary or dominant nodule and a suppressed TSH level
(a rare occurrence in practice) they need an isotope scan to demonstrate
whether the presumed hot nodule is the palpable one, in which case FNA is
unnecessary, or whether it is cold, in which case it does need a biopsy.
This is currently the only role for scintigraphy in the work-up of a
nodule in non-toxic patients, and the patient's biochemical thyroid status
should be known before proceeding to biopsy, which is never that urgent in
this clinical context.
Competing interests:
None declared
Competing interests: No competing interests
As practicing clinicians, we acknowledge the authority of the advice
in Mehanna's review [BMJ 2009; 338 : b733] but also believe that due to
its potential public health implications it should be accompanied by a
formal cost-benefit analysis which is missing from their report. As the
authors acknowledge, ultrasonography will detect thyroid nodules in 50-70%
of unselected adults in the general population but cannot obviate to the
need for fine needle aspiration cytology [FNA] cytology, which dictates
further management. Since FNA cytology, even when performed and
interpreted by experienced operators [a precondition not to be taken for
granted outside dedicated institutions] has a false negative rate of up to
6% and a non-diagnostic rate which may reach 30%, we cannot help sharing
some uneasiness at the advice that patients should be subjected to an
hemithyroidectomy [with its inherent risks, costs, and unavoidable scars]
if two aspiration procedures prove non diagnostic. The need to confirm
that the required diversion of resources is indeed worthwhile would be
even more urgent if the authors's advice [not supported by current British
and American Thyroid Associations guidelines,as the article acknowledges]
to investigate all patients with non palpable incidentally detected
nodules inferior to 10 mm were to be implemented.
Competing interests:
None declared
Competing interests: No competing interests
Radiological and Cytological Burden
Dear Sir,
We read with interest the article `Investigating the Thyroid Nodule`
by H M Mehanna et al (BMJ, 338, 21 March 2009). The authors have presented
a well organised review of the literature covering thyroid nodule
investigation.
As a group of radiologists with sub-speciality interest in ENT
imaging, there are some areas of concern that we would like to raise. The
authors cover whether incidental thyroid nodules less than 1cm should
undergo referral or investigation, and summarise that `clinicians should
be cautious about the management of patients with small or incidentally
diagnosed nodules in primary care. It may be prudent to refer to secondary
care for further investigation, such as ultrasound guided aspiration`.
The prevalence of incidental thyroid nodules is high (up to 67% on
ultrasound imaging(1)), and are becoming increasingly documented secondary
to higher resolution ultrasound, CT and MRI studies. At our institution,
in the week following publication of the article, 537 CT scans were
performed, with 166 covering all or part of the thyroid gland. Of these,
63 patients had incidental thyroid nodules (independent analysis by 2 head
and neck radiologists, SC and JO). Even ignoring incidental nodules on US
of the carotids, this creates a huge pool of patients whom the authors
suggest should be investigated further. This would have immense cost and
staffing implications for both radiology and cytology departments. If we
extrapolate our figures over a 12 month period, then over 3000 patients
would potentially require thyroid ultrasound and FNA per annum, and this
does not include patients with incidental nodules on carotid doppler
studies.
If we take previously published costs for an NHS neck ultrasound of
£90, and a fine needle aspiration as £270 (2), then based on incidental
nodules seen on CT alone we are looking at a cost potential cost to our
institution of in excess of £1,000,000 per annum. Even if we limited
investigation to patients with nodules over 10mm, then on a weekly basis,
we would see over 25 ultrasound guided FNA requests from CT imaging alone,
which would cost almost £500,000 per annum.
Data from the US show that there has been an exponential increase in
both detection of thyroid nodules, and also of thyroid malignancy. The
majority of these cases are papillary carcinoma. It should be noted that
despite these increases, the rate of cancer deaths secondary to thyroid
cancer have largely remained stable. Papillary thyroid cancer, the
commonest type is after all, a relatively benign tumour with excellent
prognosis (30 year survival rate 95% (3)).
Whilst we feel that the article was well structured and
comprehensive, we also believe that suggesting secondary care referral and
investigation for all incidental thyroid nodules will be a burden that
radiology departments, cytology departments, and the NHS as a whole cannot
handle. Rather than suggesting further investigation / referral for all
incidental nodules, we should be concentrating our efforts on discovering
the very small minority of nodules which will lead to symptomatic thyroid
cancer during the patient’s lifetime. In the meantime, we should remember
the undoubted anxiety and stress that further investigation will cause for
the patients and their families, as well as the overall cost and staffing
implications to the NHS.
References:
1. Mitchell J, Parangi S. The thyroid incidentaloma: an increasingly
frequent consequence of radiologic imaging. Semin Ultrasound CT MRI. 2005;
26: 37-46.
2. Jones R, Spendiff R, Fareedi S, Richards PS. The role of
ultrasound in the management of nodular thyroid disease. Imaging. 2007;
19(1): 28-38.
3. Davies L, Welch HG. Increasing incidence of thyroid cancer in the
United States, 1973-2002. JAMA 2006;295:2164-7.
Competing interests:
None declared
Competing interests: No competing interests